Without using code, you could probably use something like this
select tablea.*, tableb.*
INTO tmp1
from tablea left join tableb.id= - tablea.id
The tricks are that
the tables must not have any same column name
only one table is allowed to have an autonumber field
the condition tableb.id should never equal -tablea.id (this is so that the join never succeeds, so no actual data is retrieved from b aside from the column types)
If you need to replace tablea, you can
drop table tablea
and follow up with
select *
into tablea
from tmp1
The drawback is that all relationships (if any existed) are now gone.